The invention is in the field of intravenous administration of fluids to a patient in a clinical setting, and particularly concerns the warming of such fluids while they are being intravenously-administered to a patient.
Fluids which are administered intravenously to a patient consist typically of blood-based fluids and non-blood fluids, all referred to as "IV fluids." As is known, blood-based fluids are held in cool storage at approximately 4.degree. C. until they are used. Non-blood fluids are usually stored at room-temperature.
Intraveneously-administered fluids are a major cause of conductive heat loss in patients and can contribute to patient hypothermia. As is known, hypothermia poses a significant peril in an emergency, and during or after surgery. When fluid must be intraveneously-administered to patients in such circumstances, the threat of hypothermia is compounded.
In the art, it is known to warm fluids prior to administering them intravenously. Further, mechanisms are available for heating fluids during intravenous administration. In one such mechanism, the IV tube used to deliver the fluid is immersed in a liquid, such as a water bath, whose temperature is elevated by an electrical hot plate heater. In another apparatus, a plastic cassette in series with the IV tube is placed against a hot plate to warm the fluid as it runs through the cassette.
All of these methods of fluid warming have limitations. The water bath apparatus is bulky, poses the danger of electrical shock and is inconvenient to use because care must be given to storage and transport of the heating liquid in which the tubing is immersed. The drawbacks of the cassette heater are manifold. The cassette is expensive and it adds resistance to the flow of fluid. The heating element must directly contact the cassette. Because of the high thermal resistance from the element to the cassette, the rate of heating may be insufficient to adequately heat IV fluid flowing at the usual clinical rates. Adjustment of the rate of heating or flow poses the danger of over-heating the fluid, which can damage the components of blood-based compositions.
Therefore, there is an evident requirement for a means and method by which intravenously-administered fluid can be warmed quickly, efficiently, safely, and without the bulkiness and inconvenience of the prior art of warming devices. Preferably, addition of a fluid heating capacity to the normal set of surgical or emergency equipment would not result in a need for extra equipment to heat the fluid.